THE RABBIT. 349 



posterior to the origin of the pronator teres, and passing 

 into a long tendon which is inserted into the proximal end 

 of the second metacarpal : the insertion is best seen at a 

 later stage : cut through and reflect. 



423. The flexor profundus digitorum, or flexor 

 perforans (fl.p.d}, a large muscle, the chief flexor of the 

 digits, and made up by the union of four heads 



(a). The superficial head arises from the inner con- 

 dyle of the humerus just posterior to the origin of the flexor 

 carpi radialis, and in common with the palmaris ( 424) : cut 

 it through near its origin and reflect. 



(b). The ulnar head lies deeper than and anterior to 

 the foregoing, by the reflection of which it is exposed : it 

 arises from the inner condyle of the humerus in common 

 with the flexor sublimis ( 425). 



(c). The radial head arises from the proximal part of 

 the posterior surface of the radius. 



(d). The middle head arises from the posterior surface 

 of the ulna. The four heads unite at the distal end of the 

 fore-arm to form a common tendon, the insertion of which 

 is best seen at a later stage of the dissection ( 427). 



424. The palmaris (//), a small, slender muscle arising 

 with the superficial head of the deep flexor from the inner 

 condyle of the humerus and passing into a long tendon 

 which becomes lost in the palmar fascia, or sheet of 

 connective tissue covering the ventral surface of the manus, 

 sending off also a small slip which is inserted into the 

 ungual phalanx of the pollex : cut through and reflect. 



425. The flexor sublimis digitorum (fl.s.d}, or flexor 

 perforatus, lying immediately beneath the superficial head 

 of the flexor profundus : it arises in common with the ulnar 

 head of the latter from the inner condyle of the humerus, 

 and divides distally into four tendons, which pass, superficial 



